Question

2. Which one of the following statements about measuring the mass of an isolated star (a star that is not in a binary star system) is correct?
a) the mass of the star can be measured accurately only if its luminosity and temperature can be measured
b) the mass of the star cannot be measured accurately
c) the mass of the star can be measured accurately only if its distance can be found
d) the mass of the star can be measured accurately in several ways

3. What is parallax?
a) angle taken up by the size (e.g. diameter) of an object, as seen by an observer
b) shift in angular position of an object as the observer moves
c) apparent shift in position of an object as the observer moves
d) distance to an object, measured in parsecs

4. The surface temperature of a nearby star can be determined most precisely by measuring what parameters?
a) relative strengths of emission lines from different atoms and ions in the star's spectrum
b) relative strengths of absorption lines from different atoms (e.g., H, Ca) and molecules (e.g., TiO) in the star's spectrum
c) Doppler shift of the star's spectral lines
d) position on the star on the H-R diagram

5. Spica (in Virgo) and Hador (in Centaurus) have about the same temperature. However, Hador has roughly four times the luminosity of Spica. What can you determine about the relative radii of these two stars? Spica is about
a) twice the diameter of Hador
b) half the diameter of Hador
c) the same diameter as Hador
d) one-quarter the diameter of Hador

Answer 1